2.0-ás bios sem segít?
http://www.asrock.com/mb/download.asp?Model=775i945GZ&s=775

az integrált videót használod?
Esetleg annak a módját átállítani másmilyenre hátha az kavar be ()
http://img522.imageshack.us/img522/160/06012009001fr6.jpg

DVMT Mode Select
Use this option to adjust DVMT mode. Configuration options: [Fixed Mode],
[DVMT Mode] and [Fixed+DVMT Mode]. The default value is [DVMT Mode].
DVMT (Dynamic Video Memory Technology) is an architecture that offers
breakthrough performance for the motherboard through efficient memory
utilization. In Fixed mode, a fixed-size fragment of the system memory is
allocated to the graphics core. In DVMT mode, the graphics driver allocates
memory as needed for running graphics applications and is cooperatively
using this memory with other system components. In Fixed+DVMT mode,
the graphics processor gets a fixed-size chunk of 64MB of memory and up
to 64MB of dynamically-allotted memory. This mode guarantees that at least
64MB of memory is available to the graphics core, with a possibility to
increase this amount to 128MB, if necessary.
DVMT/FIXED Memory
You are allowed to adjust the shared memory size in this item if you set
DVMT Mode Select as [DVMT Mode]. Configuration options: [64MB], [128MB]
and [Maximum DVMT].

Olyasmit írnak a 945GZ chipsetes lapoknál, hogy max 2GB ramot támogat... nem tudom ez igaz -e. Meg kéne nézni mondjuk everest progival, hogy látja e a modulokat 2x2GB-osnak. A windows kiírja a 4GB-ot a Vezérlőpult\Minden vezérlőpultelem\Rendszer részen? Vagy már eleve ott is csak 2.87GB szerepel?